El Niño strengthened over the past month, with sea surface temperature anomalies exceeding +2.0°C in the eastern equatorial Pacific [Fig. 1]. The July Niño index values were +1.4°C in Niño-3.4, +1.7°C in Niño-3, and +2.9°C in Niño-1+2 [Fig. 2]. The equatorial subsurface temperature index (average from 180°-100°W) increased during July [Fig. 3], reflecting a deeper-than-average thermocline [Fig. 4]. Subsurface temperature anomalies were significant, reaching +10.0°C at depth. Low-level westerly wind anomalies and upper-level easterly wind anomalies extended from the western to east-central equatorial Pacific. Convection and rainfall were enhanced from the central to eastern Pacific and were suppressed over Indonesia [Fig. 5]. The traditional and equatorial Southern Oscillation indices were significantly negative, with values near 2 standard deviations during July. Collectively, the coupled ocean-atmosphere system reflected a strengthening El Niño.

The CPC Official ENSO outlook, which synthesizes multiple models from North America and abroad, indicates El Niño will continue to strengthen through the end of the year [Figs. 6-7-8]. During the October-December 2026 season, there is a 69% chance of a historic event that would exceed the strength of previous El Niño events dating back to 1950 (+2.5°C or more for a 3-month RONI value). With an event of this magnitude, the chances of experiencing impacts consistent with El Niño are larger, but they are not guaranteed (see CPC outlooks for probabilities of seasonal anomalies). In summary, El Niño is strengthening, with a greater than 90% chance of a very strong event during the Northern Hemisphere fall and winter 2026-27.